If you or anyone else are interested in the above lines, the following may be of some help.
"Dugdales Visitation of Yorkshire" Gives Ellerkers of Yolton(Youlton), Ellerkers of Alne, Ellerkers of Doncaster.
"Visitation of Yorkshire in 1584/5 & 1612" (R.Glover 1875) Gives Ellerkers of Risby, Ellerkers of Ellerker, Ellerker of Youlton.
G.Oliver "History of Beverley" Also gives Ellerker of Ellerker
The above publications may be available at large Reference Libraries (Hull may have copies) but worth checking out any library that may hold quite old history books. Inter-Library Loan might be worth a go.